1. Field of Invention
This invention relates generally to biofeedback therapeutic techniques, and in particular to a rhythmic biofeedback technique adapted to induce beneficial relaxation through exercise, and to a system for carrying out this technique.
2. Status of Prior Art
An individual's ability to mentally control certain of his physiological functions such as body temperature or blood pressure is known as self-regulation. For hundreds of years in the Far East, Yogis and Zen Buddhists have practiced the art of self-regulation. But with the exception of those committed to transcendental meditation, self-regulation techniques have not been widely practiced in Western society, possibly because many disorders induced or aggravated by stress which lend themselves to alleviation by self-regulation can more readily be treated by medication. Thus, a muscle contraction or tension headache as well as migraine, a vascular headache that is more painful than a tension headache, can, to some degree, be relieved by aspirin and other drugs. Such medication does not do away with stress factors responsible for the headache but serves only to moderate the symptoms. Moreover, aspirin and other drugs, when taken frequently and in large doses, often have deleterious side effects.
In recent years, biofeedback techniques have been developed which represent a more effective form of self-regulation. In biofeedback, an involuntary or unconscious physiologic process, such as the heart beat or the brain wave, is made perceptible to the senses, thereby making it possible for the individual to manipulate the process by conscious mental control.
Stress is expressed in many ways, and may be manifested by a headache or by high blood pressure. Of overriding importance in stress therapy is learning to relax and thereby reduce tension and its physiological consequences. With biofeedback, one is able to achieve mental and physical relaxation by being fed back information regarding an unconscious physiological process. This information is derived by means of a non-invasive sensor which measures peripheral skin temperature or skin resistance, heart rate, blood pressure, pulse rate, and some other process variable.
Thus, a signal from an electromyograph is indicative of varying levels of muscular activity; the higher the signal amplitude, the greater the amount of muscular tension. A high level of muscular tension reflects a high degree of stress, giving rise to tension headaches, facial pain and tics, and other stress-related illnesses. By means of a biofeedback system, one can monitor a specific physiologic process and derive therefrom a visible or audible signal indicative of the process. In this way, the user can manipulate the process being monitored by learning to control the signal it yields. By biofeedback one can reduce muscle tension, slow down a rapid heart rate, regulate blood flow to alleviate circulatory problems and, in general, relax the nervous system.
The efficacy of biofeedback is well established. Thus, in the article by Sidney Leber, M.D., "Biofeedback in Clinical Psychiatric Practice" appearing in Psychiatric Opinion of October 1979, the author states that patients previously dependent on medication for migraine and other stress-related conditions which are responsive to feedback "can reduce their medications to a line of last defense rather than continue to routinely ingest medications as a way of life."
The difficulty experienced with existing biofeedback systems is that they require a fairly long training period before the user can obtain beneficial effects. The reason for this is that internal stress conditions are not a constant; and when the user first turns on his unit, he may then be in a fairly relaxed state. The unit therefore lacks, as it were, a primer; for unless the user is in a state of stress, he has nothing to work against for purposes of stress management.